Rectenna

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A rectenna (rectifying antenna) is a special type of receiving antenna that is used for converting electromagnetic energy into direct current (DC) electricity. They are used in wireless power transmission systems that transmit power by radio waves. A simple rectenna element consists of a dipole antenna with a diode connected across the dipole elements. The diode rectifies the AC induced in the antenna by the microwaves, to produce DC power, which powers a load connected across the diode. Schottky diodes are usually used because they have the lowest voltage drop and highest speed and therefore have the lowest power losses due to conduction and switching. [1] Large rectennas consist of an array of many power receiving elements such as dipole antennas.

Contents

A printed meshed rectenna lighting an LED from a Powercast 915 MHz transmitter Meshed1GHzPrintedRectenna.jpg
A printed meshed rectenna lighting an LED from a Powercast 915 MHz transmitter

Power beaming applications

The invention of the rectenna in the 1960s made long distance wireless power transmission feasible. The rectenna was invented in 1964 and patented in 1969 [2] by US electrical engineer William C. Brown, who demonstrated it with a model helicopter powered by microwaves transmitted from the ground, received by an attached rectenna. [3] Since the 1970s, one of the major motivations for rectenna research has been to develop a receiving antenna for proposed solar power satellites, which would harvest energy from sunlight in space with solar cells and beam it down to Earth as microwaves to huge rectenna arrays. [4] A proposed military application is to power drone reconnaissance aircraft with microwaves beamed from the ground, allowing them to stay aloft for long periods.

A wearable millimeter-wave textile rectenna fabricated on a textile substrate for harvesting power in the 5G K-bands (20-26.5 GHz) Millimeter wave textile rectenna.jpg
A wearable millimeter-wave textile rectenna fabricated on a textile substrate for harvesting power in the 5G K-bands (20–26.5 GHz)

In recent years, interest has turned to using rectennas as power sources for small wireless microelectronic devices. The largest current use of rectennas is in RFID tags, proximity cards and contactless smart cards, which contain an integrated circuit (IC) which is powered by a small rectenna element. When the device is brought near an electronic reader unit, radio waves from the reader are received by the rectenna, powering up the IC, which transmits its data back to the reader.

Radio frequency rectennas

The simplest crystal radio receiver, employing an antenna and a demodulating diode (rectifier), is actually a rectenna, although it discards the DC component before sending the signal to the headphones. People living near strong radio transmitters would occasionally discover that with a long receiving antenna, they could get enough electric power to light a light bulb. [5]

However, this example uses only one antenna having a limited capture area. A rectenna array uses multiple antennas spread over a wide area to capture more energy.

Researchers are experimenting with the use of rectennas to power sensors in remote areas and distributed networks of sensors, especially for IoT applications. [6]

RF rectennas are used for several forms of wireless power transfer. In the microwave range, experimental devices have reached a power conversion efficiency of 85–90%. [7] The record conversion efficiency for a rectenna is 90.6% for 2.45 GHz, [8] with lower efficiency of about 82% achieved at 5.82 GHz. [8]

Optical rectennas

In principle, similar devices, scaled down to the proportions used in nanotechnology, can be used to convert light directly into electricity. This type of device is called an optical rectenna (or "nantenna"). [9] [10] [11] Theoretically, high efficiencies can be maintained as the device shrinks, but to date efficiency has been limited, and so far there has not been convincing evidence that rectification has been achieved at optical frequencies. The University of Missouri previously reported on work to develop low-cost, high-efficiency optical-frequency rectennas. [12] Other prototype devices were investigated in a collaboration between the University of Connecticut and Penn State Altoona using a grant from the National Science Foundation. [13] With the use of atomic layer deposition it has been suggested that conversion efficiencies of solar energy to electricity higher than 70% could eventually be achieved.

The creation of successful optical rectenna technology has two major complicating factors:

  1. Fabricating an antenna small enough to couple optical wavelengths.
  2. Creating an ultra-fast diode capable of rectifying the high frequency oscillations, at frequency of ~500 THz.

Below are a few examples of potential paths to creating diodes that would be fast enough to rectify optical and near-optical radiation.

Geometric diodes

A promising path towards creating these ultrafast diodes has been in the form of "geometric diodes". [14] Graphene geometric diodes have been reported to rectify terahertz radiation. [15] In April 2020, geometric diodes were reported in silicon nanowires. [16] The wires were shown experimentally to rectify up to 40 GHz, but that was instrument limited, and theoretically may be able to rectify signals in the THz region as well.

See also

Related Research Articles

<span class="mw-page-title-main">Diode</span> Two-terminal electronic component

A diode is a two-terminal electronic component that conducts current primarily in one direction. It has low resistance in one direction, and high resistance in the other.

The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies.

<span class="mw-page-title-main">Microwave</span> Electromagnetic radiation with wavelengths from 1 m to 1 mm

Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz. In all cases, microwaves include the entire SHF band at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations.

<span class="mw-page-title-main">Rectifier</span> Electrical device that converts AC to DC

A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The reverse operation is performed by an inverter.

<span class="mw-page-title-main">Terahertz radiation</span> Range 300-3000 GHz of the electromagnetic spectrum

Terahertz radiation – also known as submillimeter radiation, terahertz waves, tremendously high frequency (THF), T-rays, T-waves, T-light, T-lux or THz – consists of electromagnetic waves within the ITU-designated band of frequencies from 0.3 to 3 terahertz (THz), although the upper boundary is somewhat arbitrary and is considered by some sources as 30 THz. One terahertz is 1012 Hz or 1000 GHz. Wavelengths of radiation in the terahertz band correspondingly range from 1 mm to 0.1 mm = 100 µm. Because terahertz radiation begins at a wavelength of around 1 millimeter and proceeds into shorter wavelengths, it is sometimes known as the submillimeter band, and its radiation as submillimeter waves, especially in astronomy. This band of electromagnetic radiation lies within the transition region between microwave and far infrared, and can be regarded as either.

<span class="mw-page-title-main">Wireless power transfer</span> Transmission of electrical energy without wires as a physical link

Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system, a transmitter device, driven by electric power from a power source, generates a time-varying electromagnetic field, which transmits power across space to a receiver device, which extracts power from the field and supplies it to an electrical load. The technology of wireless power transmission can eliminate the use of the wires and batteries, thus increasing the mobility, convenience, and safety of an electronic device for all users. Wireless power transfer is useful to power electrical devices where interconnecting wires are inconvenient, hazardous, or are not possible.

The radio spectrum is the part of the electromagnetic spectrum with frequencies from 1 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).

<span class="mw-page-title-main">Terahertz time-domain spectroscopy</span>

In physics, terahertz time-domain spectroscopy (THz-TDS) is a spectroscopic technique in which the properties of matter are probed with short pulses of terahertz radiation. The generation and detection scheme is sensitive to the sample's effect on both the amplitude and the phase of the terahertz radiation.

<span class="mw-page-title-main">Gunn diode</span> Form of diode

A Gunn diode, also known as a transferred electron device (TED), is a form of diode, a two-terminal semiconductor electronic component, with negative resistance, used in high-frequency electronics. It is based on the "Gunn effect" discovered in 1962 by physicist J. B. Gunn. Its largest use is in electronic oscillators to generate microwaves, in applications such as radar speed guns, microwave relay data link transmitters, and automatic door openers.

<span class="mw-page-title-main">Electronic component</span> Discrete device in an electronic system

An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are not to be confused with electrical elements, which are conceptual abstractions representing idealized electronic components and elements.

<span class="mw-page-title-main">Space-based solar power</span> Concept of collecting solar power in outer space and distributing it to Earth

Space-based solar power is the concept of collecting solar power in outer space by solar power satellites (SPS) and distributing it to Earth. Its advantages include a higher collection of energy due to the lack of reflection and absorption by the atmosphere, the possibility of very little night, and a better ability to orient to face the sun. Space-based solar power systems convert sunlight to some other form of energy which can be transmitted through the atmosphere to receivers on the Earth's surface.

<span class="mw-page-title-main">Optical rectification</span>

Electro-optic rectification (EOR), also referred to as optical rectification, is a non-linear optical process that consists of the generation of a quasi-DC polarization in a non-linear medium at the passage of an intense optical beam. For typical intensities, optical rectification is a second-order phenomenon which is based on the inverse process of the electro-optic effect. It was reported for the first time in 1962, when radiation from a ruby laser was transmitted through potassium dihydrogen phosphate (KDP) and potassium dideuterium phosphate (KDdP) crystals.

<span class="mw-page-title-main">Heterostructure barrier varactor</span>

The heterostructure barrier varactor (HBV) is a semiconductor device which shows a variable capacitance with voltage bias, similar to a varactor diode. Unlike a diode, it has an anti-symmetric current-voltage relationship and a symmetric capacitance-voltage relationship, as shown in the graph to the right. The device was invented by Erik Kollberg together with Anders Rydberg in 1989 at Chalmers University of Technology.

<span class="mw-page-title-main">Ferdinand-Braun-Institut</span>

The Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH) is a research institute, which is a member of the Gottfried Wilhelm Leibniz Scientific Community. The institute is located in Berlin at the Wissenschafts- und Wirtschaftsstandort Adlershof (WISTA), its research activity is applied science in the fields of III-V electronics, photonics, integrated quantum technology and III-V technology

<span class="mw-page-title-main">Optical rectenna</span>

An optical rectenna is a rectenna that works with visible or infrared light. A rectenna is a circuit containing an antenna and a diode, which turns electromagnetic waves into direct current electricity. While rectennas have long been used for radio waves or microwaves, an optical rectenna would operate the same way but with infrared or visible light, turning it into electricity.

<span class="mw-page-title-main">Terahertz metamaterial</span>

A terahertz metamaterial is a class of composite metamaterials designed to interact at terahertz (THz) frequencies. The terahertz frequency range used in materials research is usually defined as 0.1 to 10 THz.

The following outline is provided as an overview of and topical guide to electronics:

A graphene antenna is a high-frequency antenna based on graphene, a one atom thick two dimensional carbon crystal, designed to enhance radio communications. The unique structure of graphene would enable these enhancements. Ultimately, the choice of graphene for the basis of this nano antenna was due to the behavior of electrons.

A nanophotonic resonator or nanocavity is an optical cavity which is on the order of tens to hundreds of nanometers in size. Optical cavities are a major component of all lasers, they are responsible for providing amplification of a light source via positive feedback, a process known as amplified spontaneous emission or ASE. Nanophotonic resonators offer inherently higher light energy confinement than ordinary cavities, which means stronger light-material interactions, and therefore lower lasing threshold provided the quality factor of the resonator is high. Nanophotonic resonators can be made with photonic crystals, silicon, diamond, or metals such as gold.

Geometric diodes, also known as morphological diodes, use the shape of their structure and ballistic / quasi-ballistic electron transport to create diode behavior. Geometric diodes differ from all other forms of diodes because they do not rely on a depletion region or a potential barrier to create their diode behavior. Instead of a potential barrier, an asymmetry in the geometry of the material creates an asymmetry in forward vs reverse bias current.

References

  1. ↑ Guler, Ulkuhan; Sendi, Mohammad S. E.; Ghovanloo, Maysam (2017). "A dual-mode passive rectifier for wide-range input power flow". 2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS). pp. 1376–1379. doi:10.1109/MWSCAS.2017.8053188. ISBN   978-1-5090-6389-5. S2CID   31003912.
  2. ↑ US 3434678 Microwave to DC Converter William C. Brown, et al, filed 5 May 1965, granted 25 March 1969
  3. ↑ "William C. Brown". Project #07-1726: Cutting the Cord. 2007–2008 Internet Science & Technology Fair, Mainland High School. 2012. Retrieved 2012-03-30.
  4. ↑ Torrey, Lee (1980-07-10). "A trap to harness the sun". New Scientist . 87 (1209): 124–127. ISSN   0262-4079 . Retrieved 2012-03-30.
  5. ↑ "76.09 — Radio transmitter lights antenna bulb".
  6. ↑ "Over to you: Mythical electricity?". The Daily Telegraph. 2004-11-24. Archived from the original on 2009-06-28. Retrieved 2009-06-25.
  7. ↑ Zhang, J. (2000). Rectennas for RF wireless energy harvesting (PhD Thesis). University of Liverpool.
  8. 1 2 McSpadden, J. O., Fan, L., and Kai Chang, "Design and Experiments of a High-Conversion-Efficiency 5.8-GHz Rectenna," IEEE Trans. Microwave Theory and Technique, Vol. 46, No. 12, December 1998, pp. 2053–2060. https://ieeexplore.ieee.org/document/739282
  9. ↑ Sharma, Asha; Singh, Virendra; Bougher, Thomas L.; Cola, Baratunde A. (2015-10-09). "A carbon nanotube optical rectenna". Nature Nanotechnology. 10 (12): 1027–1032. Bibcode:2015NatNa..10.1027S. doi:10.1038/nnano.2015.220. PMID   26414198.
  10. ↑ "First optical rectenna -- combined rectifier and antenna -- converts light to DC current". EurekAlert! (Press release). 2015-09-28.
  11. ↑ Patent application WO 2014063149 relates.
  12. ↑ "New solar technology could break photovoltaic limits" (Press release). University of Missouri. 2011-05-16.
  13. ↑ Poitras, Colin (2013-02-04). "UConn Professor's Patented Technique Key to New Solar Power Technology" (Press release).
  14. ↑ Zhu, Z. (2013). Rectenna Solar Cells. New York, USA: Springer. pp. 209–227.
  15. ↑ Zhu, Zixu; Joshi, Saumil; Grover, Sachit; Moddel, Garret (2013-04-15). "Graphene geometric diodes for terahertz rectennas". Journal of Physics D: Applied Physics. 46 (18): 185101. Bibcode:2013JPhD...46r5101Z. doi:10.1088/0022-3727/46/18/185101. ISSN   0022-3727. S2CID   9573157.
  16. ↑ Custer, James P.; Low, Jeremy D.; Hill, David J.; Teitsworth, Taylor S.; Christesen, Joseph D.; McKinney, Collin J.; McBride, James R.; Brooke, Martin A.; Warren, Scott C.; Cahoon, James F. (2020-04-10). "Ratcheting quasi-ballistic electrons in silicon geometric diodes at room temperature". Science. 368 (6487): 177–180. Bibcode:2020Sci...368..177C. doi:10.1126/science.aay8663. ISSN   0036-8075. PMID   32273466. S2CID   215550903.
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